Three-dimensional (3-D) sensing and imaging has been the subject of research due to its diverse benefits and applications. Some exemplary applications of 3-D imaging include mapping and computer visualization. Presently, 3-D information for purposes of mapping and computer visualization is obtained using photogrammetry. Photogrammetry is based on comparing two or more photographic images taken by one or more cameras from different positions with respect to an object being mapped. Common points are then identified on each image and a line-of-sight, or ray, is constructed from the camera location to the identified points on the object. The 3-D image and the range of the object can be determined using the intersection of these rays through the use of triangulation. Photogrammetry, however, does not allow for the generation of images in poor visibility environments, such as turbid environments. Instead, in poor visibility environments, a 3-D image can be obtained using time-gated imaging or laser scanning methods. However, these methods require expensive, specialized equipment that uses a specialized light source thereby limiting their practical range, especially in daylight conditions.
Computer-aided tomography (CAT) can also provide 3-D images. CAT is an imaging method that employs tomography in which digital geometry processing is used to generate a 3-D image of the internals of an object from a large series of two-dimensional X-ray images taken around a single axis of rotation. Although optical CAT is capable of providing high-resolution 3-D images of convex objects, its capability is limited with respect to occlusions and concave objects.
Accordingly, a need exists for a system and method that can efficiently provide 3-D imaging of various-shaped objects in all types of environmental conditions.